Food Allergies

Food allergy symptoms occur most often in babies and children but can appear at any age. Foods that you have eaten for years without problems can cause allergies.

An allergy occurs when something causes your body's natural defenses to overreact. Some 40-50 million Americans have an allergy of some kind, but food allergies are rare. Up to 4 percent of adults have food allergies.

Food Allergy Symptoms

An allergic reaction to food, often called food allergies, can cause mild to serious symptoms such as:

Some mild food allergy symptoms may be caused by a food sensitivity rather than an allergic reaction. An allergist can help determine if it is a true allergic reaction.

Shellfish, peanuts and tree nuts are the most common food allergens for adults. Milk, eggs, soy, wheat, shellfish, peanuts and tree nuts are the most common food allergens for children.

Food allergy causes:

The body's natural defense network is called the immune system. It keeps you healthy by fighting off infections and other dangers to good health. Most people have no problem eating many kinds of foods. An allergic reaction occurs when the immune system attacks a specific food or something in a food by mistake. This battle causes:

Blood vessels to swell up,

Smooth muscles to contract, and

Skin areas to become red, itchy and swollen

Why do I have food allergy?

If both your parents have allergies, you have about a 75 percent chance of being allergic. If one of your parents is allergic, or if one of your relatives from either side has allergies, you have a 30-40 percent chance of having some form of allergy yourself. If neither parent has allergy, the chance is only 10-15 percent.

The amounts of a food or a kind of food you eat, and how often you eat, it may be important to why you become food allergic.

Which foods are most likely to cause allergy?

Almost any food can start an allergy. Peanuts, tree nuts and shellfish often cause severe food allergies.

Someone allergic to a food may also react to related foods. A person allergic to walnuts may also react to pecans. Persons allergic to shrimp may also react to crab and lobster. A person allergic to peanuts may have problems with soy, peas or certain kinds of beans.

Most food allergy patients only react to one or two foods. Someone allergic to pecans may not have to stop eating all nuts. This should be discussed with your allergist.

Food intolerances

Food intolerances differ from a food allergy, as the immune system is not involved when a person is intolerant to a food. Two common intolerances, lactose intolerance and Celiac disease are discussed here.

Lactose Intolerance

Lactose intolerance occurs when an individual's small intestine does not produce enough of the lactase enzyme. Therefore, affected individuals are not able to digest lactose, a type of sugar found in dairy products.

The symptoms of lactose intolerance typically occur within 30 minutes to 2 hours after ingesting dairy products. Large doses of dairy may cause increased symptoms.

Celiac Disease

An adverse reaction to gluten is known as celiac disease or "celiac sprue". This disease requires a lifelong restriction of gluten, which is found in wheat, rye, and barley, and perhaps oats. These grains and their by-products must be strictly avoided by people with celiac disease.

Celiac disease causes damage to the lining of the small intestine, which prevents the proper absorption of nutrients in foods. This is turn can cause a person with Celiac disease to become malnourished.

Celiac disease can cause many symptoms, including bloating and gas, diarrhea, constipation, headaches, itchy skin rash, and pale mouth sores, to name a few. The symptoms may vary amongst affected individuals.